Progressive Overload
Over time the volume of work you perform and the weight lifted should increase. If it is not, you are not getting stronger.

Keep a Journal
If you do not know how much work you are performing and how much weight you are using, you cannot regulate progress.

Use the Correct Reps and Sets
In general 3-5 sets of 2-5 reps will make you stronger. 3-5 sets of 6-15 reps will put on muscle and 1-3 sets of 15-50 reps will train the joints and ligaments. All of these should be done, but remember the objective of your workout and use the appropriate combination.

Train the body as a whole
While isolation and split routines have their merits for building muscle, they are pointless when it comes to strength. You should train different exercises on different days, but think movements not body parts.

Make your Torso Strong
The torso is the source of all strength. Do a lot of hypers and good mornings, side bends, leg raises and ab wheel and lots of rowing.

Make your grip strong
The strongest men always have the strongest grips too. A lack of grip strength is typically the primary reason why many jacked and huge guys are weak for their size. Do farmer’s Walks, deadlifts, lots of chin ups and towel chin ups, shrugs and never ever use straps or gloves.

Be athletic
Having a certain amount of explosiveness and coordination goes a long way to making you strong. Nothing fancy, just jump and throw things in various ways, maybe as a warm up.

Start Easy, Progress Slow
Getting strong is all about building training momentum. This requires the body to be fully adapted and comfortable with the routine you are following. So introduce additions slowly and increase the volume and intensity at a gradual pace. This way you will not feel it when you are training at your limit and will be able to hold on to that intensity longer.

Be Consistent
A large part of strength development is the nervous system. It regulates how much force you can produce and thus makes you stronger. As such, consistent effort will teach the nervous system how to use your current musculature better and how to generate more force- think of it as strength practice rather than training. If you are inconsistent, the body will never be able to tap into your full potential.